Serpo
21st February 2012, 01:14 PM
Our Universe is filled with things we cannot yet understand and explain.
Scientists have just discovered a strange humming sound at the center of our galaxy and a cloud traveling close to the speed of light.
Compared to the rest of the galaxy, the emission is really peculiar because it differs in many ways. What could possibly generate it?
Images produced by the Planck satellite have revealed an enormous cloud of electrons traveling near the speed of light in the heart of our Galaxy, the Milky Way. These electrons interact with the Galaxy's magnetic field to produce a haze of microwave radiation seen by Planck.
"The images reveal two exciting aspects of the galaxy in which we live," said Planck scientist Krzysztof M. Górski from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Warsaw University Observatory in Poland.
"They show a haze around the center of the galaxy, and cold gas where we never saw it before." Following an orbit that shields the telescope from thermal radiation from both the Sun and the Earth, the Planck satellite is the third major space-based observatory designed specifically to make a full sky map of the Cosmic Microwave Background (CMB) radiation.
This CMB is the afterglow of the Big Bang, and provides valuable information about the structures of the Universe.
However, in the process, Planck also provides the most detailed view of the Milky Way at microwave wavelengths.
Scientists have used the new Planck data to reveal the mysterious haze with unprecedented clarity.
"The haze comes from the region surrounding the center of our Galaxy and looks like light produced when energetic electrons and positrons accelerate through magnetic fields."
http://www.messagetoeagle.com/images/mysthummilkyway2.jpg Bottom image: Top panel: A full sky view of the Galactic Haze as seen by Planck. The image shows a large haze of microwaves towards the Galactic center indicating a cloud of very energetic particles called electrons and positrons. These energetic particles interact with the Galactic magnetic field to produce synchrotron radiation seen by Planck. Bottom panel: The same image, but with gamma-ray data from the Fermi Gamma-Ray Space Telescope added in blue. It shows the "Fermi Haze/Bubbles" (Dobler, et al 2010, Su et al 2010), which is a higher energy view of the same structure. The origin of these particles is still unknown, with theoretical ideas ranging from Galactic winds, to jets generated by the Galaxy's central black hole, to dark matter annihilation. Credit: ESA/Planck Collaboration
Furthermore, "It is absolutely enormous, with a height of about 35,000 light years in the Planck maps," Gregory Dobler, a postdoctoral fellow at the Kavli Institute for Theoretical Physics at UC Santa Barbara said of the haze. What makes this finding particularly compelling, however, is not just the size of the particle cloud, according to JPL Planck scientist Krzysztof Gorski. "We're puzzled, because this haze emission is brighter at shorter wavelengths than similar light emitted elsewhere in the Galaxy," Gorski said.
"It is absolutely enormous, with a height of about 35,000 light years in the Planck maps," Dobler said of the haze.
What makes this finding particularly compelling, however, is not just the size of the particle cloud, according to JPL Planck scientist Krzysztof Gorski. "We're puzzled, because this haze emission is brighter at shorter wavelengths than similar light emitted elsewhere in the Galaxy," Gorski said.
http://www.messagetoeagle.com/images/mysthummilkyway.jpg Credit: ESA/Planck Collaboration
"This tells us there are more of these very energetic particles at high energies in the haze/bubbles than there are elsewhere in the Galaxy," Dobler said. And that, he continued, is where the real mystery begins. According to current understanding, energetic particles (named cosmic-rays) like electrons and positrons are created by explosions of stars called supernovae. For most of the Galaxy this explanation holds up quite well; however, supernovae simply cannot make enough electrons and positrons at high energy to fill the huge volume occupied by the Planck haze. The question, then, is where these very energetic particles originate.
"There are many possibilities and theories," said Dobler, "ranging from Galactic winds to a jet generated by the black hole at the center of our Galaxy to exotic physics related to dark matter.
The problem is that the picture that has emerged with the Planck data, as well as the Fermi data, challenges all of the explanations. There is no Goldilocks theory yet. None of them fit the data just right."
For now the origin of the generated emission remains a mystery.
http://www.messagetoeagle.com/mysthummingmilkyway.php
also............http://www.nytimes.com/2009/10/31/science/space/31dark.html
Scientists have just discovered a strange humming sound at the center of our galaxy and a cloud traveling close to the speed of light.
Compared to the rest of the galaxy, the emission is really peculiar because it differs in many ways. What could possibly generate it?
Images produced by the Planck satellite have revealed an enormous cloud of electrons traveling near the speed of light in the heart of our Galaxy, the Milky Way. These electrons interact with the Galaxy's magnetic field to produce a haze of microwave radiation seen by Planck.
"The images reveal two exciting aspects of the galaxy in which we live," said Planck scientist Krzysztof M. Górski from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Warsaw University Observatory in Poland.
"They show a haze around the center of the galaxy, and cold gas where we never saw it before." Following an orbit that shields the telescope from thermal radiation from both the Sun and the Earth, the Planck satellite is the third major space-based observatory designed specifically to make a full sky map of the Cosmic Microwave Background (CMB) radiation.
This CMB is the afterglow of the Big Bang, and provides valuable information about the structures of the Universe.
However, in the process, Planck also provides the most detailed view of the Milky Way at microwave wavelengths.
Scientists have used the new Planck data to reveal the mysterious haze with unprecedented clarity.
"The haze comes from the region surrounding the center of our Galaxy and looks like light produced when energetic electrons and positrons accelerate through magnetic fields."
http://www.messagetoeagle.com/images/mysthummilkyway2.jpg Bottom image: Top panel: A full sky view of the Galactic Haze as seen by Planck. The image shows a large haze of microwaves towards the Galactic center indicating a cloud of very energetic particles called electrons and positrons. These energetic particles interact with the Galactic magnetic field to produce synchrotron radiation seen by Planck. Bottom panel: The same image, but with gamma-ray data from the Fermi Gamma-Ray Space Telescope added in blue. It shows the "Fermi Haze/Bubbles" (Dobler, et al 2010, Su et al 2010), which is a higher energy view of the same structure. The origin of these particles is still unknown, with theoretical ideas ranging from Galactic winds, to jets generated by the Galaxy's central black hole, to dark matter annihilation. Credit: ESA/Planck Collaboration
Furthermore, "It is absolutely enormous, with a height of about 35,000 light years in the Planck maps," Gregory Dobler, a postdoctoral fellow at the Kavli Institute for Theoretical Physics at UC Santa Barbara said of the haze. What makes this finding particularly compelling, however, is not just the size of the particle cloud, according to JPL Planck scientist Krzysztof Gorski. "We're puzzled, because this haze emission is brighter at shorter wavelengths than similar light emitted elsewhere in the Galaxy," Gorski said.
"It is absolutely enormous, with a height of about 35,000 light years in the Planck maps," Dobler said of the haze.
What makes this finding particularly compelling, however, is not just the size of the particle cloud, according to JPL Planck scientist Krzysztof Gorski. "We're puzzled, because this haze emission is brighter at shorter wavelengths than similar light emitted elsewhere in the Galaxy," Gorski said.
http://www.messagetoeagle.com/images/mysthummilkyway.jpg Credit: ESA/Planck Collaboration
"This tells us there are more of these very energetic particles at high energies in the haze/bubbles than there are elsewhere in the Galaxy," Dobler said. And that, he continued, is where the real mystery begins. According to current understanding, energetic particles (named cosmic-rays) like electrons and positrons are created by explosions of stars called supernovae. For most of the Galaxy this explanation holds up quite well; however, supernovae simply cannot make enough electrons and positrons at high energy to fill the huge volume occupied by the Planck haze. The question, then, is where these very energetic particles originate.
"There are many possibilities and theories," said Dobler, "ranging from Galactic winds to a jet generated by the black hole at the center of our Galaxy to exotic physics related to dark matter.
The problem is that the picture that has emerged with the Planck data, as well as the Fermi data, challenges all of the explanations. There is no Goldilocks theory yet. None of them fit the data just right."
For now the origin of the generated emission remains a mystery.
http://www.messagetoeagle.com/mysthummingmilkyway.php
also............http://www.nytimes.com/2009/10/31/science/space/31dark.html